Abstract:

Objective To observe the effects of bone marrow-derived meschymal stem cells (BMSCs) conditioned medium on pulmonary fibrosis of rats. Methods Fifty SD rats were randomly divided into normal control group, model group, and treatment group (A, B, and C). Rats of the model group and treatment groups were intratracheally perfused with bleomycin (5 mg/kg) and rats of the control group were intratracheally perfused with normal saline. Rats of the model group were injected with DMEM/F-12 concentrated culture medium via caudal vein on the next day. Rats of treatment groups were injected with different volumes of BMSCs conditioned medium via caudal vein. Lung tissues of rats were harvested after 20 d and hematoxylin-eosin (H-E) staining and Masson staining were performed. The hydroxyproline (HYP) level and changes of mRNA expressions of MMP-9 and TIMP-1 in lung tissues and levels of MMP-9 and TIMP-1 proteins in lung tissue homogenate were detected. Results Compared with the model group, alveolitis and pulmonary fibrosis of three treatment groups alleviated and the level of HYP decreased. The mRNA level of MMP-9 in lung tissues and the protein level of MMP-9 and the ratio of MMP-9 to TIMP-1 in lung tissue homogenate of treatment groups were higher than those of the model group and control group. Conclusion The BMSCs conditioned medium can alleviate alveolitis and pulmonary fibrosis induced by bleomycin via increasing the level of MMP-9 and the ratio of MMP-9 to TIMP-1.

Key words: pulmonary fibrosis, bone marrow mesenchymal stem cell, conditioned medium, matrix metalloproteinase 9, tissue inhibitor of metalloproteinases 1